Fifty percent of all adolescents will use some form of illicit drugs before the end of high school, 20-25% will meet criterial for depression, and many others will engage in health compromising behaviors like delinquency and violence?with consequences for their long-term health. Evidence-based interventions shown to prevent these behavioral health concerns could improve adolescent health trajectories if implemented widely in pediatric primary care. The American Academy of Pediatrics? Bright Futures recommends that pediatricians offer developmentally tailored anticipatory guidance to all parents to support their children?s healthy development, but programs providing guidance are not offered universally. This UG3-UH3 application tests the feasibility and effectiveness of implementing Guiding Good Choices, a universal, evidence-based anticipatory guidance curriculum for parents of early adolescents, in three large, integrated healthcare systems serving socioeconomically diverse families. This intervention reduced adolescent alcohol, tobacco and marijuana use, depression, and general delinquency in two previous rigorous randomized controlled trials. It also strengthened parenting practices and parent-adolescent relationship quality, both broadly protective against behavioral health concerns. Guiding Good Choices has the capacity to achieve population-level impact on adolescent health if made widely available through pediatric primary care. Parents trust pediatricians? advice regarding their children?s well-being, and current research with socioeconomically diverse groups suggests that they are eager to participate in family-focused programs offered in primary care clinics. Building on this body of research, the investigative team, in close cooperation with the NIH Healthcare Systems Research Collaboratory and healthcare systems partners, will conduct a cluster-randomized trial of Guiding Good Choices in 72 pediatric primary care practices. Half will be randomly assigned to offer the program universally to parents of adolescents ages 11 to 12, and half will serve as usual care controls. The study will use a workflow that is easy to adopt, implement, and maintain by primary care clinics to enroll families in the intervention at the adolescent well visit. We anticipate recruiting over 4,500 families into the trial. The team will use the RE-AIM framework to test implementation outcomes and effectiveness, including hypothesized reductions in several behavioral health problems (e.g., substance use initiation, mental health symptoms and diagnoses), and emergency department and inpatient service utilization. We will use data from the EHR and a supplemental behavioral health survey to monitor outcomes up to 3 years post intervention. We will also assess the feasibility and sustainability of implementing the intervention in each HCS, including health economic evaluation to understand costs in relation to value gained. Throughout the trial the investigative team will engage in ongoing dialog with HCS leaders, pediatricians, and clinic staff to ensure the intervention and implementation process fit the needs of each HCS. We anticipate that evidence of feasibility and effectiveness in three different HCS will foster broad dissemination to achieve public health impact.